Metabolic Biochemistry: Its Role in Thermal Tolerance and in the Capacities of Physiological and Ecological Function

Thermal sensitivity of cellular energy budgets in some Antarctic fish hepatocytes

“…They began to radiate into Antarctic waters in the early Tertiary, gradually adapting to the progressive cooling, which set in after the opening of the Drake passage and the formation of the circumpolar current some 25 million years ago (Eastman 1993;Arntz et al 1994). The further South into high-Antarctic waters some of these species radiated, the more they became specialized to the permanent cold through unique adaptations at molecular, cellular and systemic levels (Kock 1992;Detrich 1997;Po¨rtner et al 2005). Eventually, this even led to the loss of respiratory proteins in the white blooded Channichthyidae (Di Prisco 2000).…”

Muscle bioenergetics of speeding fish: In vivo 31P‐NMR studies in a 4.7 T MR scanner with an integrated swim tunnel

“…All parts of the NMR set-up were tested and optimized prior to exercise studies using a square bottle filled with 0.8 M NaHPO 3 2 as a phantom. Figure 3 presents 31 P NMR spectra from the phantom under different coil set-ups and positions of the sample relative to the surface receiver coil.…”

“…Muscle physiology and energy metabolism under basal and exercise conditions have received significant attention, both for an understanding of the factors enabling and limiting exercise and, more recently, for an understanding of the role of temperature adaptation and acclimation shaping exercise performance in marine animals from various climate regimes (1)(2)(3). The function and organization of muscle tissue from ectothermic animals living at low or polar tempera-tures is especially interesting, and studies revealed unique features of adaptation for living and swimming in cold waters at all organismic levels.…”

“…The function and organization of muscle tissue from ectothermic animals living at low or polar tempera-tures is especially interesting, and studies revealed unique features of adaptation for living and swimming in cold waters at all organismic levels. Briefly, cold adaptation characteristics include a specialized muscle anatomy with an increased mitochondrial proliferation (for a review, see 4), antifreeze proteins (for a review, see 5), modified membrane structures and functions using unsaturated phospholipids (e.g., 6), and specialized modes of energy metabolism including increased lipid b-oxidation rather than glycolysis (3). An increase of lipid content will facilitate oxygen diffusion in muscle (7).…”

“…An understanding of these special adaptations is becoming even more important in the framework of climate change, questioning how animals specialized on limited climate and temperature regimes can cope with rising temperatures? A model explaining the oxygen limitation of thermal tolerance has recently been developed and tested in an ecological context with the goal to explain these phenomena (1)(2)(3)10). These analyses revealed a key role for the thermal sensitivity of aerobic scope and the mechanisms shaping the thermal window of aerobic scope.…”